Biological Deterioration of Paints and Paint Films

Micro- and macroorganisms can destroy both the decorative properties and durabilities of paint films, Figs. 6.4-1 and 6.4.2. Biodeterioration of paint falls into two general categories: enzymatic degradation of protein and cellulosic thickeners that produces an irreversible viscosity loss in latex emulsion paints while still in the container, and microbial disfigurement and deterioration of both water-thinned and solvent-thinned paint films. Enzymes catalyzing the degradation of protein and cellulosic thickeners may be introduced into the paint through contaminated raw materials, storage tanks, and other equipment or be released by bacteria (and less frequently, yeast) growing actively in the liquid paint.